ACTA ENDOCRINOLOGICA (BUC)

49, XXXXY karyotype syndrome has an incidence of between 1/85 000 and 1/100 000 live births. Typical clinical features include hypogonadism, mental retardation with severe learning difficulties, craniofacial and skeletal abnormalities, but also congenital heart disease. We report on a 4 year-old boy diagnosed with severe generalized hypotonia during his first year of life. Behavioural and cognitive profiles of the case are presented. MRI shows apart from global volume loss and atrophy, scattered punctate foci of T2 signal hyperintensity in the white matter. Endocrine investigations revealed impaired GH concentration during clonidine test, low IGF-1 concentration and cryptorchidism. Long term follow-up of patients with polysomy X by a team of specialists in pediatric neurology, endocrinology and cardiology is mandatory.